Beds – Mattress – Having confined gas
Reexamination Certificate
1999-05-03
2002-02-26
Browne, Lynne H. (Department: 3628)
Beds
Mattress
Having confined gas
C005S710000, C005S706000
Reexamination Certificate
active
06349439
ABSTRACT:
This invention relates to alternating pressure pads, and in particular to alternating pressure pads of the kind used in the prevention and management of decubitous ulcers in bedridden patients.
The formation of decubitous ulcers, commonly known as bed sores, results from, amongst other things, the pressure applied to certain portions of the skin of a bedridden patient. In addition, it is well known that should the lower reflex arc be broken by, for instance, lesion of the spinal cord or of nerve roots then decubitous ulcers of unusual severity and rapidity of onset are likely to develop. It is known to meet the requirement for the prevention and management of decubitous ulcers with an alternately pressure pad comprising two sets of alternately cells: the duration of the inflation and deflation cycles may last from under two minutes for a gently massaging effect to over twenty minutes.
A low cell internal air pressure is desirable since it provides a pad which is softer and more comfortable. However, a high cell internal air pressure in the pads is generally needed to support the bony protuberances of a patient and to ensure that the patient is lifted sufficiently away from deflated cells of the pad so that adequate pressure relief is provided for parts of the body over these areas. At the high cell internal air pressure the heel portions of a patient reach an uncomfortably high pressure at their contact points with the pad surface and are known to develop sores.
Subsequent deflation to a lower cell internal pressure still maintains a high contact pressure at the heel portions.
It is known to provide means whereby the legs of a patient are supported such that their heel portions do not contact the pad surface at all. However, in such cases, the foot develops ‘foot drop’ due to lack of support of the foot at the heel. Other proposals have included providing a lower inflating pressure to the cells supporting the heel portions, but the problem of the local high contact pressure remains.
In accordance with the present invention, an alternating pressure pad comprises at least two sets of alternately inflatable cells, at least one cell comprising means to accelerate deflation of the cell subsequent to inflation. By providing accelerated deflation of the cell(s), the contact pressure at the surface of the cell is minimised, even reaching zero during a large part of the deflation cycle. The deflation of the cell is no longer reliant upon the weight of the body lying thereon and the rapid deflation of the cell from under the body part previously supported achieves very low contact pressure which in the support of heel portions is a major breakthrough in the avoidance of heel sores.
According to the invention, there is also provided an alternating pressure pad comprising at least two sets of alternately inflatable cells, at least one cell comprising means to further collapse the cell walls away from the pad surface during the deflation of the cell subsequent to inflation. This further collapse of the cell walls during deflation quickly removes the cell surface away from the body previously supported thereon and thereby provides a substantial period of time during deflation when there is very low contact pressure.
Preferably, the means may be applied externally or internally to the cell(s).
Preferably, the means comprises at least one member applying a force circumferentially to the cell when inflated. The member may be elastic or nonelastic and may be arranged internally or externally to the cell. Such a structure allows for conventional air supply systems to be used without the need for modifications, the applied force providing the accelerated deflation subsequent to inflation. Preferably, the means comprises an internal membrane arranged to restrict the shape of the cell when inflated, the membrane urging the cell to the collapsed state during deflation.
Preferably, the means comprises an inflating device having a greater rate of deflation than the rate of inflation.
Preferably, the alternately inflatable cells are inflated simultaneously.
According to another aspect of the invention there is provided a securement means for securing a pad onto a support including first and second attachment portions, the first attachment portion being connectable to a pad and the second attachment portion being connectable to a support supporting the pad and an energy absorption member connecting the first and second portions together.
The energy absorption member may be a loop of strip material secured to and extending in the longitudinal direction of the first and second portions. Alternatively, the energy absorption member may be a series of folds of strip material secured to and extending in the longitudinal direction of the first and second portions.
The portions may each be a strip of hook and pile material eg, Velcro.
Preferably the securement means includes a sheet securing device releasably secured to the first portion and more preferably secured such that its movement along the second portion is prevented. The sheet securing device is thus retained in place for attachment of sheets but can be easily removed in the event of repair or replacement.
REFERENCES:
patent: 4042988 (1977-08-01), Holliday
patent: 4336621 (1982-06-01), Schwartz et al.
patent: 4679264 (1987-07-01), Mollura
patent: 4807313 (1989-02-01), Ryder et al.
patent: 5394577 (1995-03-01), James et al.
patent: 5421044 (1995-06-01), Steensen
patent: 5634224 (1997-06-01), Gates
patent: 5701622 (1997-12-01), Biggie et al.
patent: 5745942 (1998-05-01), Wilkerson
patent: 5806572 (1998-09-01), Voller
patent: 159299 (1921-02-01), None
Cook Stephen John
Daughtery Christopher John
Brown & Raysman Millstein Felder & Steiner LLP
Browne Lynne H.
Hewitt James M
Huntleigh Technology PLC
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